292 GRASSES OF IOWA. 



by the exudation of a yellow substance by the cane. It appears 

 that this disease is quite destructive in portions of the island 

 and that it is not spread to any great extent through the air. 

 The disease starts from the seed. The general characters 

 are as follows: Here and there will be seen stools containing 

 one or more stalks with dead tops; the base of the area in such 

 cases will be found to be rotten, usually having one or more 

 cavities of considerable size occuring near the top of the stalk 

 and filled, or partially filled, with offensive matter. A micro- 

 scopical examination shows that this is not general, but local. 

 This gum is confined to the vessels, which are plugged with it. 

 The gummy substance contains a substance called vasculin. 

 The yellow gummy matter never occurred without bacte- 

 ria. The organism responsible for this disease is a rather short 

 bacillus united in chains, the rod being surrounded by a gummy 

 exudate. The evidence that this organism is the specific cause 

 of this disease is not demonstrated, since the author did not cul- 

 tivate this organism, but relied wholly on the general facts 

 and his success in inoculating healthy cane from diseased 

 plants by means of an infection needle. 



Quite recently W. R. Dodson* has given an account of red 

 cane, expressing the opinion that one or more bacterial forms 

 accompany red cane, and that the disease in question is due to 

 the breaking down of the protoplasm. No definite results were 

 obtained by Dodson. The red coloration is of common occur- 

 rence on the cut ends of cane in the standing stalks, as well as 

 those that are used for sugar purposes, and Dodson states it is 

 very common where injury occurs. I have noted its common 

 occurrence on sorghum in this state, and an examination of the 

 cultures of sorghum cane showed that Saccharomyces glutinus 

 was common, but not necessarily the whole cause. In some 

 unexplainable way this red coloring matter is produced where 

 caue is injured. We called attention to this under sorghum 

 blight. 



Mr. N. A. Cobbf describes the red rot of cane due to an 

 imperfect fungus, so that it is evident that more than one 

 organism must be considered in the reddening of cane. 



^Bacteriological Notes on Refl Cane, In Wm. O. Stnbbs' Sugar Oaa«. 1 : 173. 

 + Agrl. Gazette. N. S. Wales. 4. 806. 



